Gola Lightning arresters

Abstracts from Foreign Contemporaries

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Lightning Arresters. — The Elektrotechnische Zeitschrift describes the system of lightning protectors made by G. Gola. Instances are given in which atmospheric discharges destroyed machines while the line was protected by ordinary lightning arresters and at times when there were no thunder storms. The ordinary lightning arresters showed no signs of having been acted upon and it was found that the discharge had gone from a wire of the armature to one or several pole-shoes; although this path was much longer than to any part of the earthed case and also much longer than the air-gap of the lightning arresters. It appears, therefore, that discharges of this kind are directed by a strong magnetic field, and that in such cases large air spaces can be overcome. To protect against discharges of this kind is the office of the new lightning arrester devised by G. Gola, shown by Fig. 6. It has the form of a hollow ellipsoid consisting of two halves of iron, A B, separated by a zinc frame, F. Above one half is another half

Fig. 6. — Gola Lightning Arrester.

ellipsoid of iron, C, so that there are two air spaces between the three iron pieces. In these a strong magnetic field is produced. Two pieces of carbon, P, are placed opposite to the rim of the ellipsoid, the distance being adjustable. The exciting coil, H, of the electromagnet is in series with the line. An atmospheric charge, which distributed itself over the surfaces of the apparatus is driven by the magnetic field to the rim of the ellipsoid and is caused to discharge over to

Fig. 7. — Side View.

the carbon pieces. These lightning arresters have been installed on a mountain line where, in five months, four accidents of the type mentioned had occurred, not withstanding the machines were protected by ordinary lightning arresters.

Fig. 8. — Top View.

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